Electric transformer



Aug. 20, 1929. A. HUET 1,724,935

I ELECTRIC TRANSFORMER Filed Jan. 4, 1928 4 Sheets-Sheet 1 gm 3 J Zfgmm a Aug. 20, 1929. A. HUET 1,724,935

ELECTRIC TRANSFORIER Filed Jan. 4, 1928 4 Sheets-Sheet 2 9W 1 Mat 014M111 Aug. 20, 1929. A. HUET 1,724,935

ELECTRIC TRANSFORMER Filed Jan. 4, 1928 4 Sheets-Sheet :5

@r/Jmm M Aug. 20, 1929. A. HUET 1,724,935

ELECTRIC 'rmusr'oauna Filed Jan. 4, 1928 4 Sheets-Sheet 4 Patented ,Au'g- 2t), 1929. i I v 7 UNITED STATES PATENT OFFICE.

Ali BERT KUET, O! LOIGNIES, BELGIUM, ASSIGNOR '10 ATE'LIEBS DE CONSTRUGTIONB RECTBIQUES DE OHABLEROI SOO'IETE ANONYKE, OI BRUSSELS, BELGIUH.

anac'rmc mmsronm Application fled January 4,1988, Serlal'llo. 244,457, and in Belgium January 4,. 1

This invention relates to the construction of example, two difierent arrangements of a of electric transformers. single phase transformer in accordance with An apparatus for weldingb means of the the invention, having a heavy voltage-drop electric arc must present the ollowing elecand with a single undivided magnetic cir- 5 trical characteristics: cuit. I

(1) A fairly high voltage on open cir- Figures 2, 4, 6 and 8 are section's taken cuit, generally from 65 to 90 volts, 1n order. along the line M--N of Figures 1, 3, 5 and 7 to allowthe striking of the are. respectively. I

(2) A heavy drop of voltage on load, in Figures 9 a'nd12 represent diagrammati- 10 such away that the voltage at the terminals cally, byway of example, two arrangements 65 of the output or external circuit shall be reof transformer in accordance with the invenduced-to a value lying between and tion, for convertin three-phase current s'up volts, this value corresponding to the fall of ply into single phase current for welding I potential in the arc. y purposes. 15 .(3) The possibility of regulatin the load Figures 10 and 13 are sections taken along. current according to the quality 0 the electhe line MN of Figures 9 and 12 respectrodes em loyed and to the mass of the parts tively, to be wel ed. Figure 11 is an explanatory diagram.

These conditions are generally realized by In the forms of construction shown in 2 n Figures 1 to. 4', the primary winding 1 is (a) of a. ,grou constituted by a transwound entirely upon the core 11 and theformer and a varlable inductance placed in secondary winding 2 upon the core 12; it series with the secondary of the transformer. is desirable to make it clear that this ar- The transformer may have a heavy voltage rangement is not indispensable. The tertiary 25 drop, the inductance acting simply to limit winding 3, having the regulating or control the load current. tappings, is simp y wound around the two (b) of a transformer provided with amagcores 11 and 12, as can be seen particularly I netic shunt having an adjustable air gap in Figure 2. This tertiary winding 3 is conallowing variation of the voltage drop. nected in series with the secondary winding 30 The present invention has for its object 2, in such a way that the current circulates the construction of a transformer with varitherein in the same direction as in the secabledrop of voltage, applicable in particular ondary (as indicated by the arrows in Figto electric welding and comprising for the ures .1 and 2) or else in such a way that the purpose of voltage-drop variation neither an current circulates therein in the contrar di- 35 external inductance nor a magnetic shunt. rection (as represented diagrammatica y in The'transformer, according to the resent Figures 3 and 4). I V invention, is provided, in addition to t e priontrol tappings a b c are connected 'maryand seconda windings, with a suppleat various omts of the tertiary winding 3. mentary winding, ereinafter referred to as The fee to the primary winding 1 is ef- 40 the tertiary winding, which is arranged in fected at the points A and B. The output such a way as to embrace practically only circuit is connected .to the point A and to the dispersion flux of the transformer or a one of the points or tappings B a: b 0 part of said flux. p. for low currents (Figures 1 and 2), or to The connection of this tertiary windin in the point A and to one of the points or tapseries with one of the other windin ,eit er pings B c b a q for heavy currents mo the ,rimary or the seconda a ows of (Figures 3 and 4). re atin the value of the vdltage-drop qf In view of the fact that the resultant flux the tran ormer, as will be explained hereembraced by the tertiary winding 3 is very after. weak on open circuit, the voltage at the ter- U on the accompanyin drawings, to minals of he secondary winding 2, when the whidh reference will be made in the followoutput is nil, varies very little whatever be ing description, the same reference letters the number of tertiary coils in service; this and numerals designate the same elements condition is necessary in order to obtain an or parts. On these drawings, Figures 1, 3, eas and regular striking of the electric arc.

5 5 and 7 represent diagrammatical y by way n load, on the other hand, the tertiary two series of windings; respectively wound around the cores 11 in Figures 5 to 8.

Figures 5 and 6 represent the transformer arranged in this manner, with current circulating in the tertiary winding 3 in the same direction as in the secondary 2.

Figures 7 and 8 represent the same transformer, with current circulating in the tertiary winding3 in the direction opposite to and 12, as represented the circulation of the current in the secondary 2.

The windings are connected in such a way that on open circuit the electromotive forces generated in each portion of the tertiary Winding are practically equal and opposite. Connection is then effected as for the single winding and as represented respectively in Figures 5, 6 and 7 8.

The input to the primary winding 1 is effected at the points A and B. The output circuit is connected to the point A and to one of the terminals or tappings B a b p for low currents (Figures 5' 'and 6) or to the point A and to one of the terminals or tappings B 6 a1 g for. heavy currents (Figures 7 and 8).

It'may here be pointed out that the arrangement represented in Figures 5 to 8 comprises only three groups of windings and therefore allows the utilization of only two ingermediate regulating or control tappings a: y

. I have described above a single-phase transformer having variable drop of voltage,

applicable in particular to electric welding and comprising for the purpose of voltagedrop regulation neither an external inductance nor a magnetic shunt, the variable volt-. age-drop transformer being provided in addition to the primary and secondary windings with a supplementary or tertiary winding arranged in such a way as to embrace practically only the dispersion flux of the transformer or a part thereof, and the connection of this tertiary winding ,inseries with the secondary allowing of regulating the value of the drop of voltage and therefore the welding current.

When the outside supply is of three-phase current, the transformer apparatus according to the present invention can be connected between two phases of the three-phase system, or again in order to obtain a more favourable distribution of the current in the various phases of the supply, there may be For the sake of symmetry, the cores 11 and 13 are adapted in the diagram to receive the primary windings 1 and 3; this arrangement however is not indispensable. These primaries 1 and 3 are then coupled by the well lmown V-connection system and connected by the three terminals A, B and C to the three phases of the three-phase net work (Figures 9 and 12).

According to a well understood construction, the coupling will be carried out in such a way that the fluxes P, and I generated in the cores If and 13 will be dephased byan angle of 60. Thus the fluxes combine as indicated in Figure 11, and the core 12 is traversed by a resultant flux I equal to F times the flux I or Q, passing through one of the cores 11 or 13. The secondary winding 2 is then wound wholly around the core 12. Y

The transformer arranged in this manner presents a considerable dispersion flux when it is on load, and there is therefore a hea voltage-drop on load. It is to be noted that this dispersion flux is in phase with the output current.

In order to obtain the desired regulation, as in the case of a single-phase transformer,

there is connected in series with the secondbraces the dispersion flux wholly or in part. This tertiary winding 4 might for example be wound around the three cores as indicated in Figures 9, 10, 12 and 13; it is then connected in series with the secondary winding 2 in such a way that the current circulates therein in the same direction as in the secondary, as indicated by the arrows in Figures 9 and 10, or else in such a way that the current circulates therein in the contrary direction, as indicated by the arrows in Figures 12 and 13.

Regulating tappings a. b 0 nected to various ing 4.

When the primary supply is fed in at A, B and G, the output circuit is connected to ta pingsBcba..

the point A and to one of the ta ings B a. b c p for weak currents igures 9 and 10) or to the point A and to one of the g for heavy currents igures 12 and 13).

In order to obtain the desired regulation of the voltage-drop, the tertiary winding or a part thereof may be connected either in conunction with or in 0 position to the seconda winding, as has njex lained above.-

t is also to be noted that 1t is permissible, without exceeding the scope of the invention, to obtain the regulation of the load current by connecting the tertiary winding in series with the primary,'instead of connecting it with the secondary as has been described with reference to Figures 1 to 6.

The advantages presented by the transformer according to the invention, as comared with transformers of the ordinary ind are the following 1) Lightness; 2g Reduced overall size;

(3 Higher output due to the fact that the m etic circuit isundivided;

(4) reat simplicity of construction; gag] Very economicaldesign.

at I claim is said core, and a supplementary regulating winding embracing a plurality of corelimbs carrying said first-mentioned windings, said regulating winding being arranged to be traversed on open circuit by a resultant magnetic flux of practically nil value and on load b the dispersion flux of said first-mentione windings.

3. An electric welding transformer, comprising a magnetic core, primary'and secondary windings upon separate limbs of said core, and a supplementary winding adapted to be connected in series with one of said first-mentioned windings, said su plementary winding being wound direct y over and upon the same core-limbs as one of said first-mentioned windin 4. An electric welding trans ormer, comprising a magnetic core, primary and secondary windings wound upon limbs of said core, a tertiary regulating windin said regulating winding embracing a p urality of core-limbs carrying said first-mentioned windings, and means for connecting said regulating winding in reversible series'with one of said first-mentioned windings.

5. An electric welding transformer, comprising a magnetic core, primary and secondary windings upon separate limbs of said core, a tertiary regulating winding wound to give variable taps, said regulatin winding embracing the same limbs of sai magnetic core as one of said first-mentioned windings and being traversed on load by the disperslon flux leaking between said firstmentioned windings, and reversible means for connecting one of said first-mentioned windings in series with the variable taps of said regulating winding.

In testimony whereo I hereunto afiix my signature.

ALBERT HUETQ 

